LAMMPS (28 Mar 2023 - Development)
dimension       3
units           micro
atom_style      sph

variable        a equal 0.1             # lattice spacing         micrometers
variable        L equal $a*10
variable        L equal 0.1*10
variable        T equal 300.
variable        kB equal 1.3806504e-8   # picogram-micrometer^2/(microsecond^2-Kelvin)
variable        rho_0 equal 1.          # density                   picograms/micrometer^3
variable        c_0 equal 10.           # speed of sound            micrometers/microsecond
variable        mu equal 1.             # dynamic viscosity         picogram/(micrometer-microsecond)
variable        h equal $a*4.0          # kernel function cutoff    micrometers
variable        h equal 0.1*4.0          
variable        mass equal $a*$a*$a*${rho_0}
variable        mass equal 0.1*$a*$a*${rho_0}
variable        mass equal 0.1*0.1*$a*${rho_0}
variable        mass equal 0.1*0.1*0.1*${rho_0}
variable        mass equal 0.1*0.1*0.1*1
variable        dt equal 5e-4           # timestep                  microseconds
variable        skin equal 0.1*$h
variable        skin equal 0.1*0.4

region          box block -$L $L -$L $L -$L $L units box
region          box block -1 $L -$L $L -$L $L units box
region          box block -1 1 -$L $L -$L $L units box
region          box block -1 1 -1 $L -$L $L units box
region          box block -1 1 -1 1 -$L $L units box
region          box block -1 1 -1 1 -1 $L units box
region          box block -1 1 -1 1 -1 1 units box
create_box      1 box
Created orthogonal box = (-1 -1 -1) to (1 1 1)
  1 by 1 by 1 MPI processor grid
lattice         sc $a
lattice         sc 0.1
Lattice spacing in x,y,z = 0.1 0.1 0.1

create_atoms    1 box
Created 8000 atoms
  using lattice units in orthogonal box = (-1 -1 -1) to (1 1 1)
  create_atoms CPU = 0.002 seconds

mass            * ${mass}
mass            * 0.001
set             group all sph/rho ${rho_0}
set             group all sph/rho 1
Setting atom values ...
  8000 settings made for sph/rho

pair_style      sdpd/taitwater/isothermal $T ${mu} 76787    # temperature viscosity random_seed
pair_style      sdpd/taitwater/isothermal 300 ${mu} 76787    
pair_style      sdpd/taitwater/isothermal 300 1 76787    
pair_coeff      * * ${rho_0} ${c_0} ${h}
pair_coeff      * * 1 ${c_0} ${h}
pair_coeff      * * 1 10 ${h}
pair_coeff      * * 1 10 0.4

variable        vx_sq atom vx*vx
variable        vy_sq atom vy*vy
variable        vz_sq atom vz*vz
compute         v_sq all reduce ave v_vx_sq v_vy_sq v_vz_sq
variable        vx_sq_check equal c_v_sq[1]*${mass}/${kB}/$T
variable        vx_sq_check equal c_v_sq[1]*0.001/${kB}/$T
variable        vx_sq_check equal c_v_sq[1]*0.001/1.3806504e-08/$T
variable        vx_sq_check equal c_v_sq[1]*0.001/1.3806504e-08/300
variable        vy_sq_check equal c_v_sq[2]*${mass}/${kB}/$T
variable        vy_sq_check equal c_v_sq[2]*0.001/${kB}/$T
variable        vy_sq_check equal c_v_sq[2]*0.001/1.3806504e-08/$T
variable        vy_sq_check equal c_v_sq[2]*0.001/1.3806504e-08/300
variable        vz_sq_check equal c_v_sq[3]*${mass}/${kB}/$T
variable        vz_sq_check equal c_v_sq[3]*0.001/${kB}/$T
variable        vz_sq_check equal c_v_sq[3]*0.001/1.3806504e-08/$T
variable        vz_sq_check equal c_v_sq[3]*0.001/1.3806504e-08/300

fix             1 all sph

neighbor        ${skin} bin
neighbor        0.04 bin
timestep        ${dt}
timestep        0.0005

thermo          10
thermo_style    custom step time v_vx_sq_check v_vy_sq_check v_vz_sq_check

run             200
Generated 0 of 0 mixed pair_coeff terms from geometric mixing rule
Neighbor list info ...
  update: every = 1 steps, delay = 0 steps, check = yes
  max neighbors/atom: 2000, page size: 100000
  master list distance cutoff = 0.44
  ghost atom cutoff = 0.44
  binsize = 0.22, bins = 10 10 10
  1 neighbor lists, perpetual/occasional/extra = 1 0 0
  (1) pair sdpd/taitwater/isothermal, perpetual
      attributes: half, newton on
      pair build: half/bin/atomonly/newton
      stencil: half/bin/3d
      bin: standard
Per MPI rank memory allocation (min/avg/max) = 14.29 | 14.29 | 14.29 Mbytes
   Step          Time      v_vx_sq_check  v_vy_sq_check  v_vz_sq_check 
         0   0              0              0              0            
        10   0.005          0.70973271     0.71495693     0.71910087   
        20   0.01           0.90418096     0.88845437     0.89659567   
        30   0.015          0.9590736      0.97880338     0.9619016    
        40   0.02           0.98533774     0.96057682     0.95600448   
        50   0.025          0.96433662     0.96650071     0.95509683   
        60   0.03           0.96598029     0.96373656     0.96734888   
        70   0.035          0.95433045     0.98004764     0.96255924   
        80   0.04           0.97872906     0.95987289     0.96623598   
        90   0.045          0.99913888     0.99255731     0.95616142   
       100   0.05           0.98872675     0.97141018     0.95338841   
       110   0.055          0.97794592     0.97389258     0.98473719   
       120   0.06           0.98389266     0.96716284     0.95504862   
       130   0.065          0.98572886     0.96680923     0.95599065   
       140   0.07           0.97602684     0.97580081     0.9886878    
       150   0.075          0.99172003     0.95027467     0.96028033   
       160   0.08           0.96793247     0.94590928     0.95644301   
       170   0.085          0.94167619     0.98048861     0.93439426   
       180   0.09           0.97277934     0.97383622     0.96900866   
       190   0.095          0.96647288     1.0027643      0.96230782   
       200   0.1            0.94864291     0.95902585     0.96398175   
Loop time of 55.7542 on 1 procs for 200 steps with 8000 atoms

Performance: 154965.922 ns/day, 0.000 hours/ns, 3.587 timesteps/s, 28.697 katom-step/s
99.6% CPU use with 1 MPI tasks x no OpenMP threads

MPI task timing breakdown:
Section |  min time  |  avg time  |  max time  |%varavg| %total
---------------------------------------------------------------
Pair    | 55.642     | 55.642     | 55.642     |   0.0 | 99.80
Neigh   | 0          | 0          | 0          |   0.0 |  0.00
Comm    | 0.060977   | 0.060977   | 0.060977   |   0.0 |  0.11
Output  | 0.0066393  | 0.0066393  | 0.0066393  |   0.0 |  0.01
Modify  | 0.028354   | 0.028354   | 0.028354   |   0.0 |  0.05
Other   |            | 0.01623    |            |       |  0.03

Nlocal:           8000 ave        8000 max        8000 min
Histogram: 1 0 0 0 0 0 0 0 0 0
Nghost:          16389 ave       16389 max       16389 min
Histogram: 1 0 0 0 0 0 0 0 0 0
Neighs:      1.456e+06 ave   1.456e+06 max   1.456e+06 min
Histogram: 1 0 0 0 0 0 0 0 0 0

Total # of neighbors = 1456000
Ave neighs/atom = 182
Neighbor list builds = 0
Dangerous builds = 0
Total wall time: 0:00:56
